Detecting Envelope Stress by Monitoring β-Barrel Assembly (Cell. 2014. 159(7):1652-64.)

報告日期: 2015/04/07
報告時間: 15:10/16:00
報告學生: 謝承陸(以英文報告)
講評老師: 黃一修
附件下載: 下載[1462-1425857434-1.pdf]  下載[1462-1425857434-2.pdf] 

Detecting envelope stress by monitoring β-barrel assembly

Cho SH, Szewczyk J, Pesavento C, Zietek M, Banzhaf M, Roszczenko P, Asmar A, Laloux G, Hov AK, Leverrier P, Van der Henst C, Vertommen D, Typas A, Collet JF

Cell. (2014). 159, 1652-64

Speaker: Cheng-Lu Hsieh                                Date: 7 April 2015  15:10-16:00

Commentator: Dr. I-Hsiu Huang                      Place: Room 602

Abstract

The cell envelope of Gram-negative bacteria is consists of the outer membrane (OM), peptidoglycan and inner membrane (IM), which provides protection from adverse environmental conditions and permeability to molecular transmission. The cell envelope also contributes environment sensing. Therefore, it should be strictly regulated to maintain its integrity. In many signaling transduction systems, the δE stress response has been known to sense the envelope perturbation and facilitate transcription of stress response genes. However, other signaling transduction systems associated with envelope damage are not well studied. The Rcs phosphorelay system, is a complex bacterial signaling transduction system. It contains a two-component system that regulates diverse physiological functions including growth rate, envelope surveillance, and two proteins IgaA and RcsF, which acts as negative regulator of the Rcs signaling system and signal sensor on outer membrane, respectively. In this study, the authors demonstrated that RcsF lies upstream of IgaA in the Rcs signaling cascade, and activates the Rcs system by interacting with IgaA. Subsequently, based on the pull-down assay, the authors found that the RcsF interact with BamA and OmpA. BamA is a major component of the β-barrel assembly machinery, playing a central role in signal transduction by interacting with RcsF, and funneling it to OmpA to display on cell surface under non-stress condition. When cell envelope stability is interfered by chemical drugs targeting the cell membrane or peptidoglycan or mutation in genes associated with envelope assembly, newly synthesized RcsF interact with IgaA, rather than binding with BamA, resulting in activation of the Rcs system. These results elucidated the role of RcsF in Rcs signaling pathway in E. coli under stress condition.

Reference

Farris, C., Sanowar, S., Bader, M.W., Pfuetzner, R., and Miller, S.I. (2010).Antimicrobial peptides activate the Rcsregulon through the outer membranelipoprotein RcsF. J. Bacteriol. 192, 4894-4903.